Risk factors for serious digitalis toxicity:
(1) advanced age, especially with comorbid disease
(2) electrolyte abnormalities:
(2a) hypokalemia
(2b) hyperkalemia
(2c) hypercalcemia
(2d) hypomagnesemia
(3) acute hypoxia
(4) respiratory alkalosis
(5) acute myocardial infarction or ischemia
(6) high grade atrioventricular block or ventricular tachycardia
(7) direct current cardioversion
(8) hypothyroidism
(9) impaired renal function
(10) impaired hepatic function
(11) increased sympathetic tone
(12) overdose
(13) increased serum digitalis concentration
(14) drug interactions resulting in increased serum digitalis levels (quinidine, quinine, verapamil, amiodarone, spironolactone, erythromycin, tetracycline, propafenone)
where:
• Erythromycin may be associated with a prolonged QTc interval.
